Trench box



y 0, 1968 DE WITT MCKINLEY 3,394,509

TRENCH BOX Filed Sept. 6; 196 46 6b 420 a? YI/IIII/III' De Witt McKinley ATTORNEYS United States Patent 3,394,509 TRENCH BOX De Witt McKinley, 6728 Fortune Road,

' Fort Worth, Tex. 76116 Filed Sept. 6, 1966, Ser. No. 577,331 2 Claims. (Cl. 52-221) ABSTRACT OF THE DISCLOSURE A trench box construction, characterized by the provision of an open-topped channel member the upper portions of the side walls of which have horizontal surfaces each containing a pair of spaced parallel longitudinal grooves. One groove of the pair contains compressible seal means, and the other is provided with at least one serrated wall and is adapted to receive screw means for securing a horizontal cover member in sealed relation to the channel member.

This invention relates generally to an improved trench box construction, and more particularly to a trench box including means for rigidly securing a cover member in fluid tight sealed relation to the upper portions of the side walls of a generally channel-shaped body member. In accordance with the invention, at least the upper side wall portions of the body member contain in the horizontal upper surfaces thereof first and second pairs of spaced longitudinal grooves that receive cover securing screws and compressible cover sealing members, respec tively. As a consequence of the invention, the need for screw threaded bores in the body and/or cover members is eliminated.

Various types of trench box constructions have been proposed in the prior art for mounting cables, conduits and the like in the surfaces of concrete floors, walls or ceilings that are poured in situ. Examples of the known trench box constructions are presented by the patents to Hoseason No. 2,812,654, Stuessel et al. No. 3,204,378, Hudson et al. No. 3,029,964 and Reiland No. 3,061,663. A major drawback of the known trench box constructions is the rather high manufacturing cost that results from the skilled labor and expensive machines required to achieve proper tolerances between the mating parts of the assemblies. A further problem is providing a trench box construction that is not only water tight but also sufficiently rigid to withstand the stresses that are developed during the pouring of concrete thereabout.

The present invention was developed to meet the above criteria for trench box design and to afford the further economical advantage that through the use of suitable longitudinal grooves, the requirement for accurately drilled threaded bores in the body or cover members is completely eliminated, whereby at least the critical mating portions of the trench box cover and body portions may be formed by extrusion from a suitable material such as aluminum. Owing to the rigid structure obtained by the'cover to side wall connections of the box, it is no longer necessary to build the rather expensive conventionalwooden forms for the pouring of concrete about the trench box. The construction is such that the trench box body may be filled temporarily with a suitable ballast material (such as sand or gravel) to stabilize the box during the pouring of the concrete. As distinguished from the cast or bent sheet metal constructions of the prior art, the trench box of the present invention may be formed substantially completely by extrusion or by the milling of longitudinal grooves, thereby reducing the cost of labor and eliminating the need of expensive hightolcrance machinery.

A primary object of the present invention is to provide a trench box construction including a horizontal top cover member and a body member having bottom and side walls, the upper portions of said side walls containing first grooves into which threaded cover fastener members are screwed. Preferably at least one vertical wall of each groove contains a plurality of vertically-spaced tooth-shaped inwardly directed longitudinal projections that are engaged by the cover fasteners. The upper portions of the side walls further include second grooves that receive resilient sealing members that are compressed when the cover is secured to the body member, whereby the trench box is sealed in a fluid type manner.

In accordance with a further object of the invention, the lower and upper portions of the body side walls are separable, whereby the upper portion may be formed inexpensively (i.e., by extrusion or by milling) and the lower side wall portions-and the bottom wall connected theretomay be formed by bending from a rather thin gauge metal sheet. The upper and side wall portions are connected by means of fasteners that are force fit into third longitudinal grooves formed in the vertical walls of the side wall upper portions.

Still another object of the invention is to provide longitudinally spaced anchor lugs that extend later-ally outwardly from the upper side wall portions to anchor the box in the concrete floor, wall or ceiling structure that is poured thereabout. The anchor lugs are secured to the body member by fasteners that are force-fit into corresponding fourth longitudinal grooves formed in the side wall upper portions.

According to another object of the inventoin, the upper side wall portions include vertically-extending longitudinal shoulders or flanges that abut the adjacent edges of the cover when fastened to the body member, whereby the trench box structure is further stabilized. The screw fasteners include head portions that are contained in corresponding recesses in the cover member, whereby the upper surface of the trench box is coplanar with the floor or wall surface.

Other objects and advantages of the invention will become apparent from a study of the following specification when viewed in the light of the accompanying drawing, in which:

FIGS. 1 and 2 are cross-section and detailed perspective views, respectively, of a first embodiment of the trench box of the present invention; and

FIGS. 3 and 4 are cross-section and tive views, respectively, invention.

Referring first to FIGS. 1 and 2, the trench box includes a body member 2 having a bottom wall 4 and a pair of side walls 6 and 8. The side walls include integral upper portions 6a and 8a having horizontal upper surfaces containing spaced parallel longitudinally extending first grooves 10 and 12 and second grooves 14 and 16, respectively. One vertical wall 18, 26 of each of the first grooves 10 and 12, respectively, contains a plurality of vertically spaced longitudinally extending tooth-shaped projections the purpose of which will be described below.

The second grooves 14, 16 have a greater width than depth, and mounted within these grooves, respectively, are resilient compressible tubular sealing members 24 formed of rubber or a suitable synthetic plastic material. The outer diameters of the tubular sealing members are substantially equal to the widths of the corresponding first grooves 14, 16, so that the upper portions of the sealing members extend slightly above the upper surfaces of the side wall upper portions 6a and 8a (as shown in FIG. 2). Adjacent their external outer edges the side wall upper portions contain upwardly extending longitudinal shoulders 6b, 8b having coplanar horizontal upper surfaces.

detailed perspecof a second embodiment of the w Projecting outwardly from the lower portions of the side walls 6 and 8 are a pair of longitudinally extending horizontal flanges 30, 23 provided with longitudinally spaced threaded bores that receive adjustable levelling screws 34. At their lower ends, the screws have head portions adapted to engage the support surface 36, whereby the trench box is supported at a desired elevation during the pouring of the concrete floor 38. Following vertical adjustment of the screws, they are maintained in place by conventional lock nuts 39.

Mounted upon the horizontal upper surfaces of the side wall upper portions 6a, 6b is a horizontal cover 49 the thickness of which equals the height of shoulders 6b, 8b. The outer edges of the cover abut the inner edges of the shoulders 6b and 8b and thereby stabilize the side walls of the trench box. Above the first grooves 10, 12 the cover contains rows of longitudinally spaced apertures that receive screw fasteners 42, respectively. Each of the fasteners includes at its upper end an enlarged head portion 42a wholly contained within a corresponding recess formed in the upper surface of the cover. At its lower end, the fastener includes a screw thread portion that is screwed into the first groove between the opposed side walls thereof. The screw has such a diameter relative to the width of the corresponding first groove that vertical indentations are formed in the groove walls by the screw threads. The upper surfaces of the head portions 40a of the screws are flat and are normally coplanar with the upper surface of the cover.

The cover and the body member are preferably formed by extrusion from a suitable extrudable material (for example, a metal such as aluminum, or a synthetic plastic material). The central portion of the cover contains a recess for receiving a decorative floor covering 44, such as asphalt or plastic tile, corresponding with a floor covering layer 46 applied to the upper surface of the concrete slab 38. As shown in FIG. 1, the second grooves 14', 16 are contained between the first grooves 10, 12.

During construction of a concrete floor containing the trench box of FIGS. 1 and 2, the body member 2 is mounted at the proper elevation relative to support surface 36 by appropriate adjustment of the screws 34, and if additional stability is desired during the pouring of the concrete floor, the box may be partially or wholly filled with ballast, such as sand or gravel. The cover 40 is then mounted in place, and screws 42 are screwed downwardly into the first grooves and 12, whereby seals 2% are compressed to provide a fluid tight seal. The concrete38 is then poured about the box, and after the concrete is set, the floor covering layer 46 is applied to the upper surface of the concrete. The cover 40 is unfastened, and if sand or gravel has been place-d in the trench box, it is now removed. Following insertion into the trench box of cables, conduits, hoses or the like, the cover is again screwed in place to compress the sealing members, whereby a sturdy, fluid-tight housing is obtained.

Referring now to the embodiment of FIGS. 3 and 4, the trench box 102 includes a bottom wall 104 and side walls 106, 108 said side walls including separable upper portions 106a and 108a, respectively. These upper portions 106a and 106b, which are preferably formed by extrusion from aluminum, have horizontal upper surfaces containing first longitudinal grooves 110, 112 parallel with and arranged between second longitudinal grooves 114, 116. As in the embodiment of FIGS. 1 and 2, the first grooves each have a vertical wall provided with horizontal projection-s for engagement by the cover securing screws 142, and the second grooves contain compressible tubular sealing members 124 that normally extend upwardly beyond the horizontal upper surfaces of the side wall upper portions 106a, 108a, respectively.

The vertical inner walls of the upper portions 106a, 108a are adapted to abut the outer surfaces of the side wall lower portions and contain horizontal third grooves 150. The upper and lower side wall portions are secured r 4 together by second fasteners 152 thatextend through corresponding openings in the side wall lower portions and are inserted by force fit into the third grooves 150.

The vertical outer walls of the upper side wall portions 106a, 108a contain horizontal fourth grooves 156 that receive, by force fit,- third fasteners 158 which secure to the trench boxside Walls a plurality of longitudinallyspaced laterally-extending anchor lugs 16!). If desired, the lower side wall portions may be provided with external laterally extending horizontal flanges and screw levelling means as in the embodiment of FIGS. 1 and 2. When these levelling means are omitted, the box merely rests directly on the supportsurface as shown.

The pouring of the concrete floor 138 is accomplished as previously described with regard to the first embodiment; the major difference being the positive anchoring of the side walls 1G6, 108 to the concrete by the embedded laterally-extending anchor lugs 160. When the concrete is set, the cover 140 is removed, the cables and/ or conduits are inserted within the box, and the cover is again secured in place by means of the cover screws 142.

While in accordance with the provisions of the patent statutes the preferred form and embodiments of the invention have been illustrated and described, it will be apparent to those skilled in the art that various changes and modifications may be made in the disclosed apparatus without deviating from the invention set forth in the following claims.

What is claimed is:

1. A trench box construction, comprising a U-shapcd metal body member including a horizontal bottom wall and a pair of vertical side walls, each of said side walls having an upper portion including a horizontal surface containing first and second spaced parallel continuous longitudinal grooves, at least one of the vertical walls of said first grooves being generally serrated to define a plurality of vertically-spaced pointed horizontal projections extending longitudinally the length thereof;

compressible resilient sealing members mounted within and extending substantially the length of said second grooves, respectively, each of said sealing members having normally a horizontal dimension generally equal to the width of the corresponding second groove and a vertical dimension slightly greater than the depth of said second groove;

the upper side wall portions of said body member having adjacent their outer edges vertical longitudinally extending flange portions extending upwardly a given distance from said horizontal surfaces;

a horizontal cover member mounted upon the horizontal surfaces of both of said side wall portions between and in contiguous engagement with said flange portions, said cover member containing two parallel longitudinally extending rows of apertures above said first grooves, respectively; and

means securing said cover member with said trench body'in surface-to-surface contact with said horizontal surfaces to compress said sealing members in said second grooves, said securing means including a plurality of fasteners extending downwardly through said apertures, respectively, and including at their lower ends screw thread portions in threaded engagement with the opposed vertical walls of the corresponding first grooves, respectively;

the body side walls including lower portions integral with said bottom wall, and upper portions separable from said lower portions, said upper portions including on their adjacent opposed faces internal vertical surfaces containing horizontal longitudinally extending continuous third grooves, said side wall lower portions having external surfaces abutting the internal vertical surfaces of said side wall upper portions, and means rigidly connecting said lower and upper side wall portions including horizontally arranged fastener means extending outwardly through apertures in said lower side wall portions and secured within said third grooves.

2. A trench box as defined in claim 1, wherein the lower side wall portions and the bottom wall of said body member comprise unitary relatively-thin sheet metal sections; wherein the upper side wall portions are formed of aluminum, said side wall upper portions including external vertical surfaces containing horizontal continuous fourth grooves; and further including laterally outwardly extending anchor lug means comprising a plurality of longitudinally spaced anchor lugs including vertical surfaces abutting said external surfaces, and auxiliary fastener means extending inwardly through apertures in said lugs for securement within said fourth grooves.

References Cited UNITED STATES PATENTS FOREIGN PATENTS Great Britain.

HENRY C. SUTHERLAND, Primary Examiner. 15 ALFRED C. PERHAM, Assistant Examiner. 

